Microfluidic chip is a hotspot in the development of Micro Total Analysis Systems (μ-TAS). The microfluidic chip technology uses the microfluidic chip as an operating platform, in combination with biological, chemical, and/or drug screening technologies. Typically, the platform is capable of completing the majority of steps in a whole analytical process, including reagent loading, separation, reaction, and/or detection. In recent years, with the rapid development of bio-chip technology, microfluidic chips play more and more important roles in the area of life science, analytical chemistry, and medicine.
For high-efficiency, rapid, and high-throughput detection of samples, chips typically need to have multiple reaction chambers and an effective transmission mode which can convey the samples or reagents to the reaction chambers. In general, microfluidic chips deliver the sample to the internal wells, channels, or holes in the chips by using external forces such as electromagnetic force, centrifugal force, and so on.
CN 101609088 A discloses a transmission fluid device. Electric force is applied to charged droplets, and the electric force controls the micro particles to move to the respective branches of the microfluidic channel. However, this method requires complex equipment that generates the electric field applied to the chip. In addition, because the liquid needs to be first converted into droplets in the electric field and be conveyed as droplets to the designated area, this method reduces the processing speed of the sample.
CN 103055973 A illustrates a delivery device based on an electro osmotic pump, which can separate different charged analytes. In general, this method only applies to charged samples and not to biological samples and non-charged samples.
Therefore, there is a need for microfluidic chips and methods of using the chips for high throughput, high sensitivity, and high accuracy reagent delivery. There is a need to not only realize the accurate dosing of sample or reagent in each reaction volume, but also avoid cross-contamination between adjacent reaction volumes.